Multifunctional molecular materials combining photoelectric conversion and second-order optical nonlinearities in LB monolayer films

A series of multifunctional dye molecules with different relative positions of electron-accepting group, E.-N-methyl-4- w2- 4-N-methyl-N-hexadecylaminophenyl.ethenylx-2-quinolinium iodide MHQ-2., E.-N-methyl-4-w2- 4-N-methyl-N- hexadecylaminophenyl.ethenylx-4-quinolinium iodide MHQ-4. and E.-N-methyl-4-w2- 4-N-methyl-N-hexadecy- laminophenyl.ethenylx-6-quinolinium iodide MHQ-6.were synthesized. These amphiphilic dye molecules were successfully transferred onto ITO electrode or quartz by Langmuir–Blodgett LB.technique. The second-harmonic generation SHG.and photoelectric conversion PEC.properties of their monolayers were studied under identical conditions. The sequence of x 2. and the photocurrent external quantum yield under the same conditions is MHQ-4)MHQ-2)MHQ-6, implying that the relative position of acceptor plays an important role in SHG and PEC properties. q2000 Elsevier Science B.V. All rights reserved.